Features - Slightly narrow entrance for better sealing to achieve more consistent power output - Special pressure point geometry reduces inconsistency between shots for more predictable trajectory and longer distances - Suitable for Marui compatible Airsoft AEGs - Super bucking works best with heavy weight BBs (.40g+) The Super bucking has a narrow entrance for more accurate shooting styles. Good for heavy weight BBs in the .40g+ range. - High durability rubber material - Suitable for most Marui-compatible AEG Hop Chamber - A solid upgrade for increased resistance in degradation from usage - Enhanced and tighter air seal for improved performance and accuracy